Glossary of terms

A

AABB (formerly American Association of Blood Banks) – the professional society for institutions and individuals involved in blood banking, transfusion medicine, and cellular therapies worldwide. Apheresis – the procedure that withdraws blood by way of a vein, removes one or more components—such as plasma, red blood cells, or platelets—and re-infuses the remainder back to the donor. (Apheresis donations are currently not able to be scheduled online.) Contact us at 1-888-GIVE-BLD for additional information on scheduling. Apheresis Angels – generous platelet donors who have joined Memorial Blood Centers’ program that includes a more extensive typing procedure, are registered in our database and, when called upon, make a special platelet donation to meet a specific patient’s time-sensitive need for platelets. Amicus Separator – a specialized instrument that collects platelets or stem cells from a single donor. Anemia – weakness, fatigue, and paleness resulting from a deficiency of red blood cells or insufficient amounts of hemoglobin molecules within the red cells. Antibody – proteins that react with antigens on red blood cells and may destroy transfused red blood cells. Anticoagulant – a substance that prevents the clotting or thickening of blood. Antigen – a substance on the surface of red blood cells that may elicit an immune response when transfused into a patient who lacks that antigen. Aplastic Anemia – caused by deficient red blood cell production by the bone marrow. Autoimmune – the process of making antibodies against one’s self. Autologous – a situation in which the donor and recipient are the same person. Autologous blood donation – blood collected from an individual to be given back to the same individual.

B

Be the Match – a national registry operated by the National Marrow Donor Program. See National Marrow Donor Program (NMDP). Blood – fluid that circulates throughout the body carrying nourishment and oxygen to the cells and tissue, at the same time, removing waste matter and carbon dioxide. Bloodmobile – mobile vehicle equipped for collecting blood from blood donors. Blood type – often abbreviated ABO, everyone’s blood falls into one of four groups or types: A, B, AB or O, with each also identified as either Rh positive or negative. For example, A positive (A+), B negative (B-), O positive (O+), etc. Blood types are inherited. Bone marrow – soft tissue located in the cavities of bones which is responsible for blood cell production.

C

Chagas Disease – caused by a parasite called Trypanosoma cruzi (T. cruzi). About 100,000 people in the U.S. are thought to be infected with it while up to 20 million people are believed to be infected in Mexico, Central and South America. Only about one percent of those infected show immediate symptoms, which can include fever, malaise, and swelling. Component – one of several different ‘parts’ that make up blood: red cells, plasma, platelets, and several types of white blood cells. Donated blood is separated into its three main components—red cells, plasma, platelets—so that patients can be transfused only with the "part" of blood needed. Creutzfeldt-Jakob Disease (CJD) – a rare condition that presents with rapidly progressive dementia and death. It usually occurs in patients over the age of 60. CrossMatch – testing between a patient and a donor’s blood to assess compatibility. CMV – acronym for cytomegalovirus, a virus that most adults are exposed to at some time in their lives. Low birth-weight infants and premature babies have immune systems that are not fully developed and, as a result, are highly susceptible to infection with CMV. Donors who do not have the presence of CMV antibodies (CMV-negative) and red blood cell and platelet units that have had leukocytes removed are called ‘CMV-Safe’.

D

Directed Donation – blood donated by a friend or family member for use by a designated patient. Donate or Donation – to give blood. A normal blood donation is comprised of a little less than one U.S. pint. Specific components of whole blood also can be donated, using apheresis technology. See Apheresis.Double Red Cell Donation – a blood separator (also called an apheresis instrument) collects and isolates red blood cells from platelets and plasma. Just one part of the blood is collected—the red cells. A double red cell donation collects double the number of red cells typically collected through a whole blood donation. See Apheresis. (Apheresis donations are currently not able to be scheduled online.) Contact us at 1-888-GIVE-BLD for additional information on scheduling.

E

e-Chair – multi-media and internet accessible chair used specifically during platelet or plasma donations. Donors are provided extra comfort and convenience during the longer donation period—one to three hours—to check email, surf the internet, work away from the office, listen to music, or watch a movie. Electrolytes – a large category of substances dissolved in plasma. The balance of water and salt is critical to good health. Electrolyte testing reveals important indicators of the amount of water and salt in your body, including: sodium, potassium, calcium, chloride, carbon dioxide, and magnesium. These chemicals are essential in many bodily functions including fluid balance, nerve conduction, muscle contraction (including the heart), blood clotting, and pH balance.

F

G

H

Hematocrit – the percentage of red blood cells found in blood. Prior to donating, hematocrit levels may be assessed to ensure that an acceptable red cell volume is present. Hemoglobin – the molecule in the red blood cell that carries oxygen. Hemoglobin combines with oxygen in the lungs and releases it in the tissues. It is what makes blood red. For volunteer blood donation, hemoglobin of at least 12.5 mg/dL is required. Hepatitis C Virus (HCV) – the most common blood-borne infection in the U.S. and a major cause of liver damage. Spread primarily via contact with infected blood, HCV is responsible for 8,000 to 10,000 deaths in the U.S. annually. Many people have the disease for years before it is detected. HLA (Human Leukocyte Antigens) Type – antigens present on most cells of the body that are unique to an individual. What may be considered to be an individual’s genetic fingerprint, there are approximately 30 million HLA genotypes. Matching donor and recipient HLA types can be particularly important in organ transplant procedures. HLA incompatibility, for example, may cause organ transplant failure.

I

L

Leukocyte – see white blood cells. Leukocyte-reduced Blood Components – a filtering process is used to create these components which help prevent reactions of fever and chills that may be associated with blood transfusion.

N

National Marrow Donor Program (NMDP) – nonprofit organization operating a national registry of unrelated potential stem cell donors called Be the Match. Memorial Blood Centers is a NMDP center that collects HPC from peripheral blood using apheresis.

P

Phlebotomy – to puncture a vein for the purpose of withdrawing blood. Plasma – the pale yellow mixture of water, proteins, and salts found in blood that functions as a carrier for blood cells, nutrients, enzymes, and hormones. Plasmapheresis – a blood separator (also called an apheresis instrument) collects and isolates plasma from platelets and red blood cells. Just one part of the blood is collected—the plasma. See Apheresis. (Apheresis donations are currently not able to be scheduled online.) Contact us at 1-888-GIVE-BLD for additional information on scheduling.Platelets – small cells in the blood that are the body’s first responder to bleeding, forming clusters to plug small holes in blood vessels and assist in the clotting process. Platelet Apheresis – a blood separator (also called an apheresis instrument) collects and isolates platelets from plasma and red blood cells. Just one part of the blood is collected—the platelets. A platelet apheresis donation collects four to six times the number of platelets typically collected through a whole blood donation. See Apheresis. (Apheresis donations are currently not able to be scheduled online.) Contact us at 1-888-GIVE-BLD for additional information on scheduling.Pooling – mixing together units of plasma or platelets that were separated from whole blood donated by multiple blood donors.

R

Recipients – people whose lives have been saved by the generous gift of blood. View StoriesRed blood cells – disc-shaped cells containing hemoglobin, which enables the cells to pick up and deliver oxygen to all parts of the body. Rh Factor – an inherited blood group on red blood cells. Approximately 85% of the U.S. population are Rh-positive (i.e., A+, B+, O+, AB+). Those who do not have the Rh factor are Rh-negative (A-, B-, O-, AB-).

S

Screening Tests – blood tests conducted to detect a disease when there is little or no evidence of a suspected disease. Sickle Cell Disease – a disease in which the affected person’s body makes an abnormal hemoglobin molecule. Most commonly diagnosed in people of African-American descent, this disease is inherited. Stem Cells – immature cells found in the bone marrow and blood stream that later develop into blood cells. They are characterized by the ability to renew themselves through mitotic cell division and differentiate into a diverse range of specialized cell types.

T

Thrombocytopenia – a low platelet count. Thrombotic Thrombocytopenic Purpura (TTP) – a disease state in which red blood cells and platelets are destroyed and the body produces excessive blood clots, which may damage the kidneys and nervous system. TRALI – acronym for Transfusion-Related Acute Lung Injury, a serious blood transfusion complication most commonly caused when antibodies are present in donor plasma. When transfused, these antibodies may activate white blood cells and cause plasma to leak into the lungs—a condition referred to as acute pulmonary edema. Women who have been pregnant are more likely to have these antibodies. Although there are currently no licensed screening tests to prevent TRALI or a single intervention that can eliminate the risk, Memorial Blood Centers takes additional steps to reduce the risk of TRALI, in particular for products that contain high volumes of plasma. Transfusion – replacing blood or blood components a body has lost as a result of surgery, an accident, or medical treatment such as chemotherapy.

W

White Blood Cells – the body's primary defense against infection which can move out of the blood stream to reach the tissues being invaded. Whole Blood – a general description for a blood donation or sample of blood taken from the venous or arterial circulation. It is composed of blood cells, platelets, and plasma.